My grandmother used to say that there's no excuse for being dirty, and I believe that there's no excuse for being unkind - or there's no excuse for not being kind.
Kindness that is Free:
1. Smiling, especially at someone who is obviously having a hard day
2. Saying "please" and "thank you"
3. Refilling the copier paper trays even if they aren't empty yet
4. Writing a short handwritten note complimenting or encouraging someone
5. Picking up someone else's lunch trash and dumping it along with your own - without being asked
6. When you ask someone how they are doing, stop and listen. Then ask a follow-up question.
I should do more of this.